Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polarographic studies on oxidation-reduction components bound with chromatophores from Rhodospirillum rubrum were carried out at 24 degrees. 1. Using a carbon-paste electrode as the working electrode, polarographic waves characteristic of oxidation-reduction components were observed in the presence, but not in the absence of Triton X-100; these waves were therefore measured in the presence of the detergent. 2. At least two kinds of oxidation-reduction components were detectable, having different half-wave potentials (E1/2); at pH 7, one had an E1/2 value of +275 mV (POC+275) and the other had a value of +60 mV (POC+60). 3. POC+275 was reduced by succinate and by NADH. Both reductions were almost completely inhibited by antimycin A, which hardly affected the reductions of ubiquinone-10 by succinate and by NADH. Most POC+275 molecules were not reduced by the substrates when quinones were extracted from the chromatophores, and the reductions were mostly restored when ubiquinone-10 was re-added. This indicates that POC+275 is functional between ubiquinone-10 and cytochrome c2 in the electron transport system. 4. POC+60 was reduced by succinate, but hardly at all by NADH. The reduction of POC+60 was not influenced either by the addition of antimycin A or by the extraction of quinones. This suggests that POC+60 is functional in the process from succinate dehydrogenase [EC 1.3.99.1] to ubiquinone-10 in the electron transport system. 5. Of the POC+275 reducible by dithionite, approximately 70% could be reduced in the absence of Triton X-100, provided that the potential of the working electrode immersed in chromatophore suspensions was set at potentials of 0 mV or lower and that the electrochemical reaction was carried out at pH 7.5. When the potential of the electrode was set at +50 mV (the same as the E1/2 value of ubiquinone-10 bound with chromatophores), and the suspension was allowed to stand for various lengths in the presence of the detergent, it was found that approximately half of the electrochemically reducible POC+275 was rapidly reduced, followed by a slow reduction. The discrepancy in the oxidation-reduction equilibrium on the basis of the E1/2 values of ubiquinone-10 and POC+275 is discussed.
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PMID:Polarographic studies in presence of Triton X-100 on oxidation-reduction components bound with chromatophores from Rhodospirillum rubrum. 18 68

Activities of succinate dehydrogenase, succinate- and NAD-H-cytochrome c--reductases, and cytochrome c--oxidase was compared in 1 g tissue homogenate and homogenate fractions made from 1 g brain tissue using various solutions. Fractionation resulted in the increased activities of NADH- and succinate cytochrome reductases, and in the loss of succinate dehydrogenase activity, cytochrome oxidase was less influenced. These phenomena are regarded as signs of the interrelation between mitochondria and other constituents of brain cell within homogenates. Maximal quantity of mitochondria isolated from homogenates is no more than 20% of all the mitochondrial homogenates (according enzyme data). The electronogram of the brain mitochondrial preparation isolated in the Krebs--Ringer solution without glucose pointed out to a high homogeneity of mitochondria in the residue.
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PMID:[Enzyme, electron microscopic and polarographic characteristics of isolated rat brain mitochondria. III. Quantitative assessment of their distribution in fractions of the homogenate]. 18 80

Antimycin-inhibited bovine heart submitochondrial particles generate O2- and H2O2 with succinate as electron donor. H2O2 generation involves the action of the mitochondrial superoxide dismutase, in accordance with the McCord & Fridovich [(1969) j. biol. Chem. 244, 6049-6055] reaction mechanism. Removal of ubiquinone by acetone treatment decreases the ability of mitochondrial preparations to generate O2- and H2O2, whereas supplementation of the depleted membranes with ubiquinone enhances the peroxide-generating activity in the reconstituted membranes. Addition of superoxide dismutase to ubiquinone-reconstituted membranes is essential in order to obtain maximal rates of H2O2 generation since the acetone treatment of the membranes apparently inactivates (or removes) the mitochondrial superoxide dismutase. Parallel measurements of H2O2 production, succinate dehydrogenase and succinate-cytochrome c reductase activities show that peroxide generation by ubiquinone-supplemented membranes is a monotonous function of the reducible ubiquinone content, whereas the other two measured activities reach saturation at relatively low concentrations of reducible quinone. Alkaline treatment of submitochondrial particles causes a significant decrease in succinate dehydrogenase activity and succinate-dependent H2O2 production, which contrasts with the increase of peroxide production by the same particles with NADH as electron donor. Solubilized succinate dehydrogenase generates H2O2 at a much lower rate than the parent submitochondrial particles. It is postulated that ubisemiquinone (and ubiquinol) are chiefly responsible for the succinate-dependent peroxide production by the mitochondrial inner membrane.
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PMID:Role of ubiquinone in the mitochondrial generation of hydrogen peroxide. 18 49

We have examined the effects of total body iron deficiency on the function of mitochondria isolated from rat hearts. Male Wistar rats were weaned at 21 days and divided into an experimental iron-deficient group and a control group. Both groups received identical diet but an iron supplement (180 mg of ferrous sulfate per kg of diet) was added for the control group. Rats were studied at 7 and 14 weeks. Iron-deficient rats weighed less than controls but showed significantly increased ventricle to body weight ratio at both 7 and 14 weeks, indicating relative cardiac hypertrophy. Isolated mitochondrial fractions from iron-deficient and control rats contained similar proportions of whole homogenate protein and succinic cytochrome c reductase activity, indicating that the fractions isolated from the experimental and control rats were comparable. In iron-deficient rats NADH cytochrome c reductase, succinic cytochrome c reductase, succinic dehydrogenase, and NADH ferricyanide oxidoreductase activities were all significantly reduced at 7 and 14 weeks. Cytochrome c oxidase activity was significantly reduced only at 14 weeks as were the concentrations of cytochromes a3, c1, and b. The rate of oxygen uptake by mitochondria was significantly lower at both 7 and 14 weeks but the P/O ratio was unaltered. We conclude that iron deficiency is associated with impairment of myocardial mitochondrial electron transport.
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PMID:The effects of iron deficiency on the respiratory function and cytochrome content of rat heart mitochondria. 18 77

In this first paper of a series comparing the membranes of normal lymphocyte populations from male outbred Syrian hamsters with those of neoplastic transformants (GD 248) induced by simian virus 40, a method is described for the isolation of representative plasma membrane (PM) fragments from both cell types. Multiple criteria were used to monitor the purity and yield of PM material after cell disruption by nitrogen cavitation and after membrane fractionation by a combination of differential centrifugation and isopyknic ultracentrifugation in dextran density gradients. Lactoperoxidase-catalyzed radioiodination before cell disruption was used as an extrinsic surface marker; Na+,K+-activated ATPase, as well as alkaline phosphatase, was used as intrinsic functional PM markers. The distribution of nuclei, mitochondria, lysosomes, and endoplasmic reticulum (ER) during fractionation was monitored by the measurement of DNA, succinate dehydrogenase and monoamine oxidase, beta-glucuronidase and glucose-6-phosphatase, and NADH:lipoamide oxidoreductase, respectively. According to the three PM markers employed, a 15- to 20-fold purification (over homogenate) and a PM yield of about 65% were obtained for both cell categories, with negligible contamination by DNA, mitochondria, lysosomes, and er. The procedure also allowed recovery of 60% of the mitochondria free of other cell elements.
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PMID:Membranes of normal hamster lymphocytes and lymphoid cells neoplastically transformed by simian virus 40. I. High-yield purification of plasma membrane fragments. 18 92

A CO-binding hemochrome was accumulated in Escherichia coli cells, when intracellular heme concentration was increased by aerobic incubation of resting cell suspensions with ALA. Reduced minus oxidized difference spectrum of the hemochrome showed peaks at 560, 530, and 430 nm and a shoulder at 575 nm. The peaks of CO reduced minus reduced difference spectrum were located at 572, 540, and 422 nm. The CO spectrum was similar to but not identical with the spectrum of cytochrome o, a known terminal oxidase in E. coli. SDS-polyacrylamide gel electrophoresis of the CO-binding hemochrome showed its molecular weight to be about 33,000. The hemochrome in crude cell-free extracts was oxidized by aeration and reduced by the addition of succinate or NADH. The reduction by succinate was inhibited by inhibitors of succinate dehydrogenase [EC 1.3.99.1], and the reduction by NADH was inhibited by 2-heptyl-4-hydroxy-quinolin-N-oxide, which is an inhibitor of electron transport in E. coli cells.
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PMID:A carbon monoxide-binding hemoprotein formed by heme accumulation in Escherichia coli. 19 71

The coupling constants J between the iron atoms in ferredoxin type iron-sulfur proteins containing binuclear clusters were evaluated by two parallel methods. The temperature dependence of the EPR linewidths and integrated abosrption intensities are both related to the energy of the first excited state. The values of J obtained were: center S-1 in succinate dehydrogenase, 90 cm-1; Rieske's iron-sulfur center, 65 cm-1; adrenodoxin, 270 cm-1. The behavior of iron-sulfur center N-1a in NADH:UQ reductase was also examined; its similarity to that of center S-1 indicates that center N-1a is also a binuclear iron-sulfur center, with J = 90 cm-1. Greater rhombic distortion present in the EPR spectrum of a binuclear cluster was associated with smaller values of J.
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PMID:Determination of the exchange integral in binuclear iron-sulfur clusters in proteins of varying complexity. 19 6

In 175 dogs myocardial infarction was produced by high ligation of descending branch of left coronary artery. At various intervals after the intervention (1, 3, 5, 10, 30, 180 days), the activities and levels of NAD, NADH, FAD, riboflavin, cytochrome C, myoglobin, some NAD-dependent Krebs cycle enzymes, and mitochondrial succinate dehydrogenase and cytochrome oxidase were determined in the infarcted zone. It was found that in the infarcted zone there occurred substantial disturbances of various links constituting the tissue oxidative chain, in the stages of substrate dehydrogenation, electron transport to oxygen molecule, and myocardial oxygen uptake. The greatest disturbances took place in the systems of NAD and NAD-dependent enzymes, whereas the succinate oxidation system sustained substantially lesser damage. The decrease inlevels of flavonoids, which was likewise observed, participated also in the mechanism inhibiting succinate dehydrogenase. The cytochrome system activity was limited by the level of cytochrome C, whose deep decrease persisted considerably long in the infarcted zone. A certain role in disturbances of oxidative processes may have been played by the decreased concentration of myoglobin, an important myocardial reservoir of oxygen.
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PMID:Some myocardial factors of biological oxidation in experimental myocardial infarction. 19 79

1. From the 57Fe hyperfine interaction in EPR spectra of reduced submitochondrial particles from the yeast Candida utilis, grown with 57Fe, it is concluded that all Fe-S centers in these particles detectable in spectra at 35-80 K are [2Fe-2S]2-(2-; 3-) centers. These are the centers 1 of NADH and succinate dehydrogenase, the Rieske Fe-S center and possibly center 2 of succinate dehydrogenase. 2. The signals of the reduced particles detectable only at temperatures below 20 K are [4Fe-4S]2-(2-; 3-) clusters. These are the centers 2,3 and 4 of NADH dehydrogenase. 3. EPR spectra of the [2Fe-2S]3- centers of Complex I and II, but not that of Complex III, display a great inequality of the Fe nuclei in the effective hyperfine interaction in the x-y direction.
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PMID:The number of Fe atoms in the iron-sulphur centers of the respiratory chain. 19 54

Characterization of the energy metabolism pattern of the specialized heart muscle of bovine heart was studied in comparison with that of the ordinary heart muscle. Mitochondrial oxygen consumption of the specialized heart muscle was significantly lower than that of the ordinary heart muscle with succinate as the substrate. On the other hand, there was no significant difference in oxygen consumption between both heart muscles with glutamate + malate as the substrates. The activity levels of succinate dehydrogenase and lactate dehydrogenase were much lower than those of the ordinary heart muscle. The isozyme pattern of LDH of the specialized heart muscle consisted of one major component of LDH-1 (H4) and that of the ordinary heart muscle consisted of two major components of LDH-1 (H4) and LDH-2 (H3M). The ratio of NADH to NAD of the specialized heart muscle was remarkably lower than that of the ordinary heart muscle. These results indicate that the specialized heart muscle depends not only upon anaerobic metabolism but also upon aerobic metabolism for its energy supply.
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PMID:Characteristics of energy metabolism in specialized muscle of bovine heart. 20 90


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